Various operations are performed in a wellbore to enable the production of fluids from, or injection of fluids into, a reservoir in a formation surrounding a section of the wellbore. Examples of operations performed in a wellbore include perforating operations (to extend perforations through any surrounding casing or liner and into a formation), fracturing operations (to create fractures in a formation), and other operations.
Certain operations involve the use of explosives. For example, perforating guns include shaped charges and detonating cords, and firing heads for perforating guns include primary and/or secondary explosives. Explosives can also be used in other types of downhole tools, such as propellants (which are considered low explosives) used in fracturing tools for performing fracturing jobs.
When components containing explosives are being handled by humans, they present a safety hazard if adequate precautions are not taken. Typically, for well applications, components containing explosives are transported from a storage facility or manufacturing facility (or other type of facility) to the well site. At the well site, the components are assembled by well operators into a tool for deployment into a wellbore. During handling by humans, electrostatic discharge (ESD) may occur, which can cause inadvertent initiation of the explosive being handled. Such inadvertent initiation of explosives can cause serious injury or even death. Typically, components such as detonators that contain explosives include circuitry for ESD protection. However, conventional ESD protection, such as those implemented with spark gaps, are not always effective due to the possibility of manufacturing defect.